The Blue Ridge Fire initially broke out just before 1 p.m. Monday near Chino Hills State Park. It was initially named the Green Fire and then changed to the Blue Ridge Fire, for Blue Ridge Drive in Yorba Linda.
Fire officials say the fire poses an immediate threat to residences in Yorba Linda.
At least one single-family home was seen damaged from flames. The blaze approached within less than 100 feet of other homes.
Evacuation orders were issued for Yorba Linda neighborhoods, according to the Orange County Sheriff's Department.
"Anyone in the affected area should evacuate immediately," the OCSD tweeted.
The sheriff's department estimated about 4,000 properties, with 10,000 people, were evacuated but OCFA officials did not say how many homes were under mandatory evacuation.
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Law enforcement alerted residents of mandatory evacuations in Brea and Chino Hills late on Monday night.
Tuesday morning, Los Angeles County officials issued an evacuation warning for residents in an area of Diamond Bar, bordered by Grand Avenue to the north, Diamond Bar Boulevard to the west, the Los Angeles/Orange county line to the south and the Los Angeles/San Bernardino county line to the east. There are no evacuation orders or warnings for Corona, according to the Orange County Fire Authority.
Firefighters were seen going through those neighborhoods telling residents to evacuate. Most packed up their things and left the area.
"This is apocalyptic," said neighborhood resident Gabriel Sanchez. "The skies are turning a different color orange. It's frightening. My daughter was so frightened. I'm glad she's safe now."
A few residents chose to stay behind, even grabbing shovels themselves to help put out smaller spot fires that were breaking out on a hillside behind their neighborhood.
The fire broke out on a day of intense Santa Ana winds throughout Southern California that triggered a red-flag warning for the area. Other fires around the region, particularly in Orange County have spread rapidly and some areas are seeing gusts in excess of 50 mph. Temperatures are cool, but humidity is very low in the brush.
The cause of the fire remains under investigation.
Blue Ridge Fire evacuation map
Please note the map may take some time to load. The map can also be seen at this link.
Authorities had not yet established an evacuation shelter but said small animals could be brought to OC Animal Care Services, 1630 Victoria Road, Tustin.
The county's Emergency Operations Center Hotline phone number is (714) 628-7085.